RESEARCH ON BORONIZATION IN HT-7 SUPERCONDUCTING TOKAMAK BY He GLOW DISCHARGE

In order to reduce the content of impurity and improve the performance of the plasma,boronization has been performed in HT-7 superconducting tokamak by using RFassistant He glow discharge（He GD）.After successfully being boronized, he good plasma parameters have been achieved:lower effective charge（Zeff）,lower loop voltage（Vp）,lower radiation power,at the same time the performance of the plasma was improved dramatically too:good recycling properties of hydrogen, lower water pressure in residual gas, extended stable operation region and quickly going to stable operation.So boronization can provide a fine first wall condition for HT-7 superconducting tokamak stable operation.